I purchased an old car this past summer and with it came some old parts like a set of front brake calipers. They were rusty but looked rebuildable so I ordered a couple of rebuild kits and a couple of new pistons. Well the pistons were stuck/rusted in place and would not move. I ended up destroying one piston getting it out but decided to find an easier way on the second caliper.

Since I own a TIG welder I elected to simply drill a hole in the back side of the caliper and use a long punch to drive the piston out of it's bore. I then tapped the hole I drilled and installed an allen style pipe plug in the hole. Now that's not going to seal so I then welded the plug in place and since I set the plug below the surface I filled the depression completely. The calipers were cast steel so welding on them poses no issues. I wouldn't expect pistons to stick as bad when the caliper is aluminum.

Someone may ask: "Why not just just buy new calipers?". Since the car is old some parts are NLA and rebuilt calipers are one item like that.